Question

Distinguish among helical, polyhedral, enveloped, and complex viruses, and provide one example of each.

Answer 1

Helical virus are synthesized of only one single protein subunit, which are stacked along the central axis in order to form a helical type structure.
Tobacco Mosaic virus is a helical virus.

Polyhedral virus as the name suggests is a virus which is synthesized with many capsids and around which nucleic acids surround itself and thus a structure of icosahedron is produced.
One such example is Adenovirus.
Adenovirus is a virus which is nonenveloped, and consist of nucleocapsid that will wrap around the genome of double stranded(ds)DNA.

Enveloped virus- The virus which exit the host cell by the process of budding and as a result of which the virus forms the envelope. Also, the infection produced by these virus depends on the envelop formed.
Example are Human Immuno virus and influenza virus.

Complex Viruses have capsid that have complex outer wall and structure like tail made of protein. The complex viruses structure are neither in the form of helical nor they are icosahedral. The protein subunits of complex virus will get assembled inside the capsid. In order to build a capsid the DNA of this virus will encode for those protein that are involved in the capsid building.
Example is Bacteriphages, these are viruses which infect bacteria. They are complex in structure as they posess head made of icosahedral, that is attached to the tail in the shape of helix and this helicalTail posess a base plate.